An organic light emitting display and a manufacturing method thereof include an improved encapsulation layer. The encapsulation layer of the organic light emitting display includes an organic layer uniformly covering bank portions and light emitting areas on a substrate; and an inorganic layer formed thicker on the light emitting areas than on the bank portions. In the organic light emitting display, the inorganic layer is thick on the light emitting area in which a sealing ability is required and the bank portion is thin in order to provide flexibility. Therefore, the encapsulation layer can be formed more easily compared to an encapsulation layer on a device in which the organic layer and inorganic layer are alternately formed at least 10 times.